WHEN Dong Nguyen, a Vietnamese software whizz, pulled his frustratingly enjoyable game “Flappy Bird” from mobile app stores last Sunday, it left both players and industry insiders scratching their heads. Flappy Bird had swiftly become the most downloaded game on both iPhones and Android phones, and was making some $50,000 a day in advertising revenues—the kind of success most game developers can barely envisage. But Mr Dong, who has rejected almost all requests for interviews, believed Flappy Bird needed its wings clipped. “It was just too addictive,” he finally told the Wall Street Journal. “I just wanted to create a game that people could enjoy for a few minutes.”

A quick look at reviews suggests that Mr Dong was right about his game’s addictiveness. Its engaging mix of simplicity and difficulty kept players hooked for hours and even days on end. Many grew increasingly angry with their own feeble scores, and with Mr Dong (some even threatened to kill him for making the game so hard). More sophisticated online games, however, don’t seem to need hours or days to influence people’s real-life behaviours. Research published in the journal Psychological Science finds that avatar-based games can do so even in the brief “few minutes” that Mr Dong had hoped his own game would occupy people.

The heroic or villainous characters that gamers adopt as online avatars have long been known to affect how they feel about themselves and how they behave offline. Online superheroes, then, are more likely to perform good deeds in real life; villains, less likely. All this, however, largely applies to long-term (that is, addicted) gamers. Gunwoo Yoon and Patrick Vargas, of the University of Illinois at Urbana-Champaign, asked a very different question: would a paltry five minutes of immersive gaming promote prosocial or antisocial actions in everyday behaviour?